LeetCode [914] X of a Kind in a Deck of Cards

 914. X of a Kind in a Deck of Cards

Easy

In a deck of cards, each card has an integer written on it.

Return true if and only if you can choose X >= 2 such that it is possible to split the entire deck into 1 or more groups of cards, where:

• Each group has exactly X cards.
• All the cards in each group have the same integer.

 

Example 1:

Input: deck = [1,2,3,4,4,3,2,1]
Output: true
Explanation: Possible partition [1,1],[2,2],[3,3],[4,4].

Example 2:

Input: deck = [1,1,1,2,2,2,3,3]
Output: false´
Explanation: No possible partition.

Example 3:

Input: deck = [1]
Output: false
Explanation: No possible partition.

Example 4:

Input: deck = [1,1]
Output: true
Explanation: Possible partition [1,1].

Example 5:

Input: deck = [1,1,2,2,2,2]
Output: true
Explanation: Possible partition [1,1],[2,2],[2,2].

 

Constraints:

• 1 <= deck.length <= 10^4
• 0 <= deck[i] < 10^4

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class Solution { public boolean hasGroupsSizeX(int[] deck) { Map<Integer, Integer> count = new HashMap<>(); for(int i : deck){ count.put(i, count.getOrDefault(i, 0) + 1); } int ret = 0; for(int i : count.values()){ ret = gcd(i, ret); } return ret>1; } int gcd(int a, int b){ if(b==0) return a; else return gcd(b, a%b); } }